I wonder if the terrestrial and celestial glory, with the moon and sun being representative have anything to do with the scripture that says:

"That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust." (Matthew 5:45)

Note that it is the Father which causes the sun to shine on all equally, regardless of their current respect or knowledge of him. And consider the moon how it is variable. In order to rise to celestial glory, to rise from the grace of the terrestrial world, is it necessary to have our hearts be converted to be like unto the Father's?

(Keep in mind that Christ does not represent terrestrial glory, but is instead a minister to those who would inherit terrestrial glory. Christ represents the fullness of celestial glory.)

Is the amount of light in each kingdom representative of the amount of glory, or rather the amount of love that we possess for mankind, as the sun shines from one end of the earth to the other? Is charity a result of knowledge of godliness that we gain when we part the veil and begin to understand God?

"He that loveth his brother abideth in the light, and there is none occasion of stumbling in him. But he that hateth his brother is in darkness, and walketh in darkness, and knoweth not whither he goeth, because that darkness hath blinded his eyes." (1 John 2:10-11)

Loving mankind includes respect for their choices, right or wrong. It includes self-sacrifice to allow them to use agency as they see fit, so that they can come away from mortality with greater knowledge and experience. It includes intelligence and wisdom to be able to know how to succor those who are suffering in darkness back to the light.